CA

noun

By · According to Wiktionary data (CC BY-SA) ·

"ca" is a 2-letter English headword indexed on PlainSpell.

The verdict

“CA” is a regularly-used English word, ranked #2,148 in English word frequency and used as a noun.

#2,148
frequency rank, English
2
letters
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Initialism of cellular automaton.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

CA vs co
0% similar
CA vs CD
50% similar
CA vs CM
50% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for CA
PropertyValue
HeadwordCA
LanguageEnglish
Part of speechNoun
Letters2
Frequency rank#2,148
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “CA” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). CA lands here:

#1#100#1K#10K#100K
← used constantlyrarely used →

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Spelling & Dictionary Insight

The English entry for CA is 2 letters long, classified as a noun. Corpus data places it at rank #2,148 in overall English word frequency, indicating it appears regularly in written and spoken text. Wiktionary records 13 distinct senses for this headword, so context determines which meaning a reader should apply.

The misspelling generator found no plausible variants for CA, and the word's spelling is regular enough that our generator found nothing worth flagging. It also participates in 20 confusable-pair relationships, "co", "CD", "CM", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

No explicit etymology string is stored for this entry, so its spelling is best explained by sound-to-letter mapping rather than etymology. The correct English form is CA, spelled C-A.

Definition

  1. 1
    Initialism of cellular automaton.
  2. 2
    Initialism of certificate authority.
  3. 3
    Initialism of armored cruiser, a type of warship.
  4. 4
    Initialism of heavy cruiser, a variant of the cruiser type of warship.
  5. 5
    Initialism of civil affairs, a military occupational specialty or branch.
  6. 6
    Abbreviation of cyanoacrylate.
  7. 7
    Initialism of chartered accountant.
  8. 8
    Initialism of cabin attendant.
  9. 9
    Initialism of central authority.
  10. 10
    Initialism of Companies Act.
  11. 11
    Initialism of communications assistant.
  12. 12
    Initialism of closed access, as opposed to open access.
  13. 13
    Initialism of conversation analysis.

This word in other languages

CA(Français)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "CA"?
"CA" is spelled C-A.
What does "CA" mean?
As a noun, "CA" means: Initialism of cellular automaton.
What words are commonly confused with "CA"?
"CA" is commonly confused with "co", "CD", "CM". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
What language does "CA" come from?
"CA" is a English word. PlainSpell covers definitions, pronunciations, and spelling data across English, Spanish, Portuguese, French, and German.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Using “CA”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is C-A - every other letter order is a misspelling in standard orthography.
  • Don't mix it up with “co” - see the side-by-side comparison. CA vs co
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list